1. Field of the Invention
The present invention relates to a disk drive device for rotating a disk.
2. Description of the Related Art
A hard disk drive is known as a medium used as a storage device in a computer. In a hard disk drive, a magnetic recording disk on which recording tracks are formed is rotated at high speed by a brushless motor. A magnetic head is placed against the surface of the magnetic recording disk with a slight distance between them for the purpose of reading/writing magnetic data contained in the recording tracks.
Japanese Utility Model Application Publication No. hei5-36647 and Japanese Patent Application Publication No. hei5-122879 disclose a type of brushless motor in which a yoke is press-fit against the inside of a hub that holds a magnetic recording disk. In this type of brushless motor, the yoke is press-fit with sufficient strength in order to prevent the yoke from being misaligned or from dropping due to impulse. Here, the press-fit strength means the pressure between the components after they are press-fit against each other.